| With the development of the country and the improvement of people’s living standards,people have a higher demand for the safety level of building structures under various actions,especially the earthquake.At the same time,many buildings are also entering the aging stage.The housing structures designed and constructed according to the previous standards have lower design standards,aging materials and serious damage.Now it is urgent to use good building materials to reinforce the existing buildings to meet the needs of the project.Ultra–high performance concrete(UHPC)has attracted wide attention in engineering due to its high compressive strength,excellent durability and good working performance.The application of it in the reinforcement of frame structure is a field of continuous exploration in the current engineering field.In order to study the seismic performance of reinforced concrete members strengthened with ultra–high performance concrete,the following works are carried out in this paper:(1)ABAQUS solid element and ABAQUS fiber beam element are used to simulate the flexural failure reinforced concrete column respectively.The simulation results show that the latter can simulate the hysteretic relationship of the member better.On this basis,ABAQUS fiber beam element is used to analyze the parameters of UHPC reinforcement thickness,UHPC reinforcement height and axial compression ratio.The results show that the horizontal strength of UHPC strengthened members of this failure type is greatly improved under low and high axial compression ratio,and the UHPC has excellent reinforcement effect.(2)ABAQUS solid element and Open Sees fiber element are used to analyze the UHPC strengthening performance of RC columns with bending shear failure and RC columns with shear failure.The applicability of the two softwares in hysteretic analysis of concrete columns is compared.The results show that the horizontal strength of flexural shear failure concrete columns and shear failure concrete columns strengthened with UHPC is greatly improved,and the effect of UHPC reinforcement is good.(3)ABAQUS solid element is used to simulate the reinforced concrete beam–column joints,and the comparison with the test shows that the simulation effect is good.The results show that the hysteretic strength of beam end is greatly improved by using UHPC to strengthen concrete beam–column joints,but the actual axial compression ratio increases from 0.05 to 0.15,and the hysteretic behavior of beam end and the stress–strain of steel and concrete change little.(4)ABAQUS fiber beam element is used to establish a 3–story and 3–bay concrete frame for quasi–static simulation,and the correctness of the model is verified by comparison with the test.On this basis,a 6–story and 3–bay frame strengthened by UHPC is established to study the mechanical responses of base shear,floor displacement and the most story drift angle under different earthquake actions.The conclusions are as follows:The simulation method,which uses fiber beam model and ignores the failure of beam–column joint,captures the main mechanical behavior and has good calculation accuracy;Under rare and frequent earthquakes,the most story drift angle of RC frame that strengthened by UHPC can be greatly reduced than that of the unreinforced frame. |
